Core bit



March 25, 1941. v R R, (M 2,235,982

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Filed June 20, 1939 2 Sheets-Shut 1 INVENQTOR.

mm? am I ATTQRNEYI R; R. CRUM 35.98

March 25, 1941..

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Filed June 20. 1939 2 Shooi-Sheot I lNVENT-OR.

- BY v 'r-ro zNEY Patented Mar. 25, 1941 UNITED "STATES P T NT OFFlCE azsassz cons arr RolandlLCrum, Whittier, Calif. 7 Application 'Iune 26,1939, Serial No. 280,099 warms (01. 255-72) data thus obtained, the driller or geophysicist may be better guided as to the proper procedure to be followed. The samples of the formations have been commonly obtained by core barrels operating on an annulus to form a core. It has also been proposed to utilize a core barrel for the reception of the core,'that may be raised or lowered through the drill string without the necessity of raising or lowering the drill string.

It' is one of the objects of this invention to improve in general, bitstructures of this character; and especially by ensuring that the cutters will be rigidly supported during the. drilling operation.

The boring of the annulus around the core is accomplishedin the present instance by the aid of disc cutters. It is another object of this invention to provide. in a core bit, a plurality of sets of cutters, for operating on diii'erent annuli, and rotatably mounted on pins that are adequately.

supported at both ends.

This invention possesses many other advantages, and has other objects which may be made more easily'apparent from a consideration of one embodiment of the-invention: For this purpose there is shown a form in the drawings accompanying and forming part 01 the present speciilcation. This form will now be descr'lbed in detail, illustrating the general principles of the invention; but it is to be understood that this detailed description is not to be taken in a, limiting sense, since the scope of this invention is best defined by the appended claims.

Referring'tothe drawings:

Figure 1 is a part sectional view of a core bit incorporating the invention, the core barrel "being shown as in placewithin the bit:

Fig. 2 is a viewsimilar to Fla. 1, the core barrel being omitted, and the section being on a plane so taken through the arm that supports an inner cutter; I

Fig. 3 is a sectional viewtaken'along plane 3-4 0111:. 1, but with the core barrel omitted;

Fig. 4 is a bottom plan view of the core bit body 65 prior to the assembly 01 the supporting arms;

Fig. 51s a sectional view taken along plane 5-5 1 of Fig. 3; and Figs. 6 and 7 are, pictorial views respectively of the arms that serve to support the outer and inner disk cutters. 5 w The bit has a body I adapted to be attached to the lower end 2 '(Fig. 1) of a" drill string, as by the usual pipe thread coupling. This bit body is hollow in order that the usual mud fluid circulation may take place through it to the various cutting elements. In this ca's the bit body is also provided with a downward y extending central hollow extension 3 shown most clearly in Fig. 5. Through this hollow extension it is intended to project an outer core barrel 4. This core barrel may be provided with an exterior sloping shoulder which rests on seat 6 in body l' immediately above the extension 3. This seat 8 is'shown to best advantage in Fig. 5.-

In thepresent instance the core which is 20,

adapted to be accommodated within the inner core barrel 1, may be cut by the aid of the cutter teeth 8 at thebottom of the core barrel 4.

In order to obtain the core, it is required that the bore in which the bit operates be cut annular-ly around the core barrel 4. For this purpose a series '0! disk cutters are used for cutting on annular surfaces or zones at the bare bottom. Thus there is a pair of outer cutters 9 and Ill (Figs. 1 and 2') which operate on the outer zone or annulus. These cutters 9 and III are disposed diametrically opposite each other with respect to the axis of the bit. The inner zone or annulus or the bore, adjacent the core barrel 4, is arranged to be operated upon by a pair of inner disk cutters II and I2, angularly spaced about the axis of the bit, irom'the outer'disk cutters 0 and I. These inner disk cutters II and- I! are also arranged diametrically opposite each 40 other with respect to the axis of the rotation of the bit structure.

The manner of supporting these disk cutters forms an important part of the invention. There will first be-described the support for one of the 5 outer disk cutters 9. It isto be understood that the other outer cutter. II is supported in identical fashion. and therefore a description of the support for cutter I will sumce for a description of both of these cutters.

A supporting arm I! (Figs- 1. 3 and 6) in the :7, tom of 'aseparate piece, is provided with an integral pin structure I. The axis I! of the pin structure is inclined .do'wnw'ardly and .in-

' wardly with respect to the .axis of rotation pt 56 a the bit. The pin structure l4 includes an enlarged base portion I6 and a reduced end portion II. The outer periphery of the portion l6 serves as the inner race of a radial roller bearing structure. This radial roller bearing structure is formed by a plurality of rollers l8. The outer race is formed by the inner cylindrical surface l9 of the cutter 9.

This radial roller bearing structure serves properly-to support the cutter disk in a rotatable manner. In order to support the thrust which occurs due to the drilling pressure, a ball bearing structure is provided inwardly of the roller bearing structure, to support the inward thrust. Thus an inner ball bearing race is formed by a collar 20 telescoping over the reduced portion ll of the pin structure. The end surface of this collar 20 abuts against theshoulder 2| formed at the end of the enlarged portion IS. The end surface of the collar 20 also overlaps the rollers ill. The outer race for the balls 22 forming the thrust bearing structure is provided by an inner surface of the cutter 9.

The manner of assembling the cutter 9 upon the pin structure is apparent from the foregoing. The cutter 9 with the rollers l8 may first be telescoped over the enlarged portion l6 of the pin structure. Then the collar 20 with the ball bearings 22 may be telescoped over the reduced portion I1.

After the arm l3 has been assembled with the cutter structure in the manner just described, it may then be appropriately attached to the bit head I. For this purpose the arm l3 may be, provided with a dovetailing longitudinal projection .23 adapted to cooperate with a corresponding groove 24 in the projection 52 integral with the body I (Figs. 3 ands). At the same time the end of the reduced portion i1 is inserted within an aperture 25 in the wall of the extension 3. The outer surface 26 of the wall of extension 3 is formed as a slanting boss contacting the adjacent surface of t e collar 20. Thus by the aid of this aperture 2 and the arm l3, the pin structure i4 is strongly supported at both ends.

The arm I3 may now be welded in place upon the bit body i. The welded-on metal'2'l is illustrated in Fig. 1 between the top fiat surface .28 (Fig. 6) of the arm i3 and the outer surface of the bitbody I. Beads of welding metal 29 (Fig. 3) may also be provided along the longitudinal edges of the arm l3. Similarly, in order to hold the reduced portion I! of the pin structure It rigidly in place, metal 30 may be welded to the end i! and serves to fill in the space between the inner periphery of the extension 3 and the end of the reduced portion ll. The act of welding can be accomplished from the inside of this extension 3 after the arm I 3 and the pin structure l4 have been placed in cooperative relationship with the bit head.

The cutters 9 and ill have lower edges which i operate upon an'outer annulus as. before stated.

The inner annulus is adapted to be cut by the aid of the inner cutters 4| and I2. Since bothe of the cutters II and I2 are supportedon the bit bodyin identical fashion, a description of the manner in which inner cutter II is supported on the bit body wilralso serve as a description of the manner of supporting the cutter l2.

These inner cutters are supported for rotation on pin structures 32 about axes 3| which slope upwardly and inwardly with respectto the axis 01' the bit body I. These pin structures-32 are,

formed integrally with separate supporting arms 33 (Figs. 2, 3 and 7). These supporting arms in general are similar in structure to the supporting arms l3 for the outer cutters 9 and I0.

In the case of the inner cutters, due to the character of the slope of axis 32, the ball thrust v bearing is provided adjacent the arm 33, to support an outward thrust. For this purpose the pin structure 32 has an enlarged base portion 34 serving as the inner race for a plurality of balls 35. The outer race is formedby an interior surface of the cutter II. The reducedportion 36 of the pin 34 serves as the inner race for a radial roller bearing structure including the rollers 31. The outer race isformed by the interior cylindrical surface 33 provided in the cutter H. The shoulder 39 between the portions 34 and 36 serves as an abutment for the left hand end of the rollers 38. A collar or washer 40 is inserted over the end portion 4! of the pin 32.

The manner of assembly of the cutter structure with respect to the arm 33 and pin 32 is apparent from the foregoing. First of all, the

cutter H with the balls is telescoped over the pin 32. Then the rollers 31 may be inserted in their races, and finally the washer or collar 43 may be placed upon the end 4i.

With the arm assembly thus united, the arm 33 may be permanently attached to the bit body i. For this purpose the arm 33 may be provided with a projection 42 adapted to dovetail within a cooperating groove 43 formed on the body I. The end 4| of the pin 32 may be inserted into a through aperture 44 in the extension 3. Thereafter the welded metal may be added to hold the assembly in place. For example, the welded metal 43 may be disposed between the top flat surface 35 (Fig. '7) of the arm 33, and the bit body. Longitudinally extending beads 41! (Fig. 3) of welded-on metal may be provided along the longitudinal edges of the arm to unite it with the corresponding surfaces of the bit body i. The end 4| of the pin 32 may be held, in place by the addition of welded metal 43 filling the space between the end of extension 4! and the aperture 33 in the extension 3. The act of welding this metal 43 may be performed from the inside of the extension 3.. 2

As shown most clearly in Fig. 2, the inner lower edge 49 of the cutter II is substantially in line with the inner diameter of the extension 3 so as tocut the core to the size corresponding to this inner diameter. The lower edge of the extension 3 may be formed with a recess 50 opposite this lower edge 43 sq as to obviate interference between the cutter H and the extension 3. Provisions are made for circulating mud fluid from the interior of the drill stem 2 to the spaces above the various cutters. For this purpose apertures 3| (Figs. 1, 2, 3 and 4) may extend downwardly from the inside of the head I to the space exterior of the extension 3. The lower ends of these apertures are so disposed as to discharge the mud fluid slightly in advance of the cutters.

] What is claimed is:

, 1. In a core bit, a body adapted to be connected to a drill string, said body having a rearms'carrying an integral pin reaching into the extension and adapted to carry a roller cutter,

said'extension continuing a substantial distance below the'gpins and having circular openings for receiving the pins, each of said openings closely encircling its associated pin, and means securing openings, the arms being joined to the body along a surface so arranged that the armsmay be placed on the body ,by moving the arms. in a direction coinciding with the direction of the axes of the pins, and means forming a key on said surface between the arm and the body to prevent lateral movement between said arm and said body.

3. The combination of claim 2, wherein some of the pins are inclined inwardly and downwardly, and others of the pins are inclined inwardly and upwardly, all with respect to ,the bit axis.

4. In a core bit, a body adapted to be connected to a drill string, said body having a reduced central portion a central hollow extension through which a core may pass, arms assembled on the body and joined thereto, each of said arms carrying an integral pin reaching into the extension, said, extension continuing beyond the pins, and having circular openings for receiving and closely encircling the associated pins, said pins being secured in the respective openings, some oi said pins being inclined upwardly and inwardly, some of said pins being inclined downwardly and inwardly, with respect to the bit axis,

each of,said pins carrying a roller cutter, means forming a. radial bearing and means forming a thrust bearing, interposed between each pin and its associated roller cutter, said thrust bearings on the downwardly inclined pins being disposed adjacent the inside face of the cutter, said thrust bearings on the'upwardly inclined pins being disposed adjacent the outside face of the cutter.

ROLAND CRUM. 

